It was endowed in 1867 by philanthropist Gan Eng Seng and other prominent leaders such as Khoo Cheng Tiong and Choo Yoke Lam. It is the oldest charitable Medical Institution in Singapore catering to all ethnic groups and a core social organisation within Chinese community in early Singapore. "Tong Chai" means "Benefit to all". This is a very appropriate name because it manifests the spirit of mutual assisstance among early Chinese immigrants. The institution also served as a social centre, a public meeting place and headquarters of Chinese guilds.
It is a two-storey building of South China palace design. It has three halls, two courtyards and ornamental gables. The institution was managed by a committee comprising of leaders from various clans.
It is now the only building owned by the Preservation of Monuments Board restored at the cost of $440,000 and it is rented out to and Arts and Crafts dealer.
